Bipolar laparoscopic instrument with replaceable electrode tip assembly

Abstract

An electrosurgical instrument for use in endoscopic procedures features an electrode assembly which can be readily connected and disconnected from the remaining body of the instrument to allow a replacement electrode assembly to be substituted. The instrument comprises an elongated rigid tube having a handle on the proximal end, the handle including a spring-loaded plunger which is connected by a push rod to a stem member disposed in the lumen of the tube near its distal end. The electrode assembly is designed to mate with the stem and when the plunger is actuated to extend the stem beyond the distal end of the tube, the electrode assembly may be installed. Retraction of the stem within the lumen of the tube serves to hold the electrode assembly in place.

What is claimed is: 
     
       1. An electrosurgical instrument for use in endoscopic procedures, comprising: (a) an elongated, rigid tube having a proximal end, a distal end and a lumen extending therebetween;   (b) a handle affixed to the proximal end of the tube;   (c) a stem member disposed within the lumen of the tube and having a proximal end, a distal end and an outer dimension corresponding to the inside dimension of said lumen whereby the stem member can slide longitudinally within the lumen, said stem member having first and second electrical contact pads and first and second radial bores,;   (d) means disposed in the handle coupled to the stem member for imparting longitudinal reciprocal movement to the stem member;   (e) a replaceable electrode assembly releasably secured to the distal end of the stem member and extending distally from the distal end of the tube, wherein the assembly includes: (i) an insulating support member having at least a portion thereof dimensioned to closely fit within the distal end of the lumen of the tube; and   (ii) a pair of bipolar electrodes extending outwardly from the support member, said electrodes having electrical terminals which are L-shaped wire segments whereby a portion of each segment engages one electrical contact pad of the stem member and a portion of each segment resides within one radial bore of the stem member; and     (f) means for coupling an electrosurgical generator to the electrode assembly.   
     
     
       2. An electrosurgical instrument as claimed in claim 1 wherein the L-shaped wire segments are retained in said radial bores when the stem member is retracted into the lumen, and said wire segments are removable from said radial bores when the stem member is moved longitudinally beyond the distal end of said tube. 
     
     
       3. An electrosurgical instrument as claimed in claim 1 wherein the stem member has a pair of grooves which extend longitudinally from the radial bores to the distal end of the stem member and within which are disposed the electrical contact pads. 
     
     
       4. An electrosurgical instrument as claimed in claim 1, 2 or 3 wherein the means disposed in the handle comprise: (a) a manually operable, spring-biased plunger slidingly received in said handle; and   (b) a push rod coupling said spring-biased plunger to said stem member.